Atom (Classic Journeys Era)
200px|rightThe atom is the fundamental building block of all matter. It is composed of three subatomic particles: electrons, which have a negative charge, protons, which have a positive charge, and neutrons, which have no charge. A stable atom has an equal number of protons and electrons, making it neutral overall. The number of protons determine the element of the atom. Two protons make helium, while twelve carbon. An elementary configuration of the atom places the protons and neutrons in a central mass called the nucleus. The electrons orbit the nucleus in a circular pattern. At best, it is oversimplifed for the general population. At worst, it is grossly inadaquete. While this model, first proposed by scientist Rutherford Bohr of Earth in 1913, is sufficient to give a broad understanding of the atom, it falls short when attempting to explain the finer details of magnetism and photon generation. For that, one must take a closer look at a more modern version of the atom. The quantum mechanical model keeps the nucleus as it is, but alters the perception of the electron. Instead of the negatively-charged particles orbitting in circular or elliptical paths, the mechanical model asserts that electrons exist in a dense cloud around the nucleus. The electrons exist in different levels of orbits, each having a higher energy level than the prior. Picture a road underneath a highway. Higher orbitals can retain a greater amount of electrons. For example, the first orbital can hold two electrons, while the second eight. Suborbitals exist within each orbital. Each suborbital has a distinct shape, and it is along this shape that the electrons that populate the orbital travel. The shapes are determined mathematically and empirically based on principles that are beyond the scope of this document. A suborbital is assigned a letter of the alphabet. The first orbital has one 's' suborbital, while the second has one 's' and one 'p.' Photons In photon generation, the atom is excited by electricity so that ground-state electrons jump to higher orbitals within the atom. When they fall back down to their original orbital, they emit a photon. Magnetism Magnetism is more complicated. As the electrons orbit the nucleus, they spin, creating a very minor magnetic field. Its partner suborbital electron spins in the opposite direction. These two spins cancel out the magnetic field. However, there are electrons in atoms that have no partner electron because of a principle called Hund's Rule. These atoms are said to be paramagnetic or ferromagnetic, and they can potentially become magnets. When in the presence of a magnet, these unpaired electrons will align themselves in relation to the field and generate their own magnetic field. It is this alignment that produces a magnet. Please note that non-permanent magnets, such as an electromagnet, are discussed in the projectiles section. Isotopes Isotopes are atoms of the same element but having differing neutrons. As we read earlier, neutrons and neutrally charged particles in the nucleus. They have no bearing on the identity of the atom, but instead differentiate between "breeds" of an element. They also determine other characteristics, such as radioactivity. An isotope is distinguished from a normal atom by a number after its name. Carbon-16 indicates sixteen neutrons instead of the normal twelve. Ions Ions are atoms with an unequal amount of electrons and protons, which effects the charge of the atom, which effects how the atom interacts with other particles (Think about a magnent). When the atom has an equal number of electrons and protons, it has a neutral charge. When there are more electrons than protons (anion), the atom has a negative charge, and it has a positive charge (cation) when there are more protons than electrons. Ions are denoted by their net charge in superscript, and number of electrons lost or gain if more than one, such as H+ or SO32-. Ions are used extensively in living things, with elements like sodium, potassium and calcium playing an important part in cells. Ions are also harnessed in ship technology, such as with ion sub-light drives. A plasma is a collection of non-aqueous ions or gas containing a proportion of charged particles. Thanks to: Wikipedia:Ion Category:Classic OtherSpace Technology